Study On Inter-Domain Routing Stability

Internet has undergone significant changes from its inception. The Internet has been divided into different administrative domains called Autonomous Systems (ASes). Within the AS, Interior Gateway Protocols are used to exchange routing information. Exterior Gateway Protocols are used to exchange routing information between Ases. The Border Gateway Protocol (BGP) is the de facto exterior gateway protocol deployed on the Internet. With the growth of the Internet, the stability of BGP has gotten the notices of expert and industry people. How to solve the instability problem of BGP has currently become the focus concerned with the research of Internet routing.The route instability is referred to as route flapping in which a route that previously existed in the routing table disappears and reappears intermittently. The reasons for BGP route instability are diverse, including Interior Gateway Protocol instability, hardware failures, software problems, CPU power insufficient, memory insufficient, network topology change, BGP routing policies conflict and routes configuration errors. Based on Project research of inter-domain routing stability and management, from national Natural Science Foundation of China, the dissertation dissertes the stability of inter-domain routing. We study some of the reasons leading to BGP routing insability and give methods to enhance BGP routing stability in term of these reasons. Some valuable results are yielded.The policy conflicts of BGP can cause route oscillations. In this paper we deeply study the route oscillation caused by BGP routing policies conflicts and present the route oscillation through simulation experiment. A method to detect policies conflicts and route oscillation caused by insistent policies is proposed. We first use the safe path problems to study the BGP route oscillation and theoretically analyze the dynamic behavior characteristics and conditions of BGP routes oscillations. We define the conception of route relative preference that is used to describe the preference relationship between two different routes to the same destination. Comparing the relative preference of selected routes, two neighboring ASes can detect the routing policies conflicts. We define a data structure, local path history, to store routes taking part in oscillation and eliminate route oscillation by damping the route reappear in the local path history. The given method can...